Out of C and CO, which is a better reducing agent at 673K?

Explanation

this can be explined thermodynamically , taking entropy and free energy changes into account .
(A)` C(s) +O_(2) to CO_(2)(g)`
(b) `2C(S) +O_(2)(g) to 2CO(g)`
Case (i) volume of `CO_(2)` produced = Volume of `O_(2)`
used .
`therefore Delta S` is very small and `Delta G` does not change with temperature .
`therefore` plot of `Delta G V_(s)` T is almost horizintal .
Case (ii) Volume of CO produced `=2xx` volume of `O_(2)` used .
`therefore Delta S` is positive and hence `Delta G` becomes inceeasingly negative as the temperature increases.
`therefore` plot of `Delta^(@)G` Vs T slopes downwards .

As can be seen from `DeltaG^(@)` Vs T plot (Ellingham digram ) lines for rthe reaction C---- gt `CO_(2)` and C---rarr CO cross at 983 K the reaction (a) isenergetically more favurable but above 673 K reaction (b) is favourable and preferred thus below 673 K both C and CO can act as a reducing agent but since CO can be more easily oxidised to`CO_(2)` than C to `CO_(2)` , therefore , below 673 K , co ismore effective reducing agent than carbon.